制备条件对Ru／Ce0．8 Zr0．2 O2催化剂上CO2甲烷化反应性能的影响

摘要

A series of Ru/Ce0.8 Zr0.2 O2 catalysts we re prepared by the impregnation method with Ce0.8 Zr0.2 O2 homoprecipitated and calcined at different temperatures as supports. The supports and the catalysts were characterized with TG-DSC, BET and H2-TPR tce hniques.It was hs own that he Ce0.8 Zr0.2 O2 calcined at 500℃formed Ce-Zr solid solution and had a proper surface area and pro e opening and a weak interaction with Ru species, leading to a significant increase in the catalytic activity.A suitable reduc tion mte hods promo ted d istribution of active speic es.The Ru/Ce0.8 Zr0.2 O2 prepared with the Ce0.8 Zr0.2 O2c alcined at 500 ℃ showed hihg activity after cla cinait on at 400 ℃ and successive reduction with H2 N・NH2・H2 O and H2 .It gavea H2 covn ersion of 93.57%,a pproaching to the equilibrium value under the oc ndi it ons of 290 ℃, 0.1 MPa, 10 000 h-1 and H2/CO2 mol ratio of 3.5.%采用均相法制得Ce0．8 Zr0．2 O2载体，并以其为载体等体积浸渍制得一系列负载型Ru催化剂。在0．1 MPa、GHSV为10000 h－1、H2／CO2为3．5（物质的量比）的条件下，对催化剂进行评价。借助TG－DSC、BET、H2－TPR等技术对所制备的载体和催化剂进行表征，结果表明，500℃焙烧的载体具有适中的比表面积和孔径并形成了Ce－Zr固溶体，与载体形成弱相互作用的Ru能够显著提高催化剂的活性，适宜的还原方式能促进活性组分的均匀分布。采用500℃焙烧的载体浸渍RuCl3溶液，干燥后在400℃焙烧，并使用水合肼和H2两次还原后的催化剂活性最高，在290℃时，H2转化率可达到93．57％。